1. Field of the Invention
The present invention relates to an optical apparatus such as a camera in which a light modulation element such as a transmission type liquid crystal display element is disposed in a finder optical system.
2. Description of the Related Art
Many cameras have previously been proposed in which a transmission type liquid crystal element is disposed in the visual field of a finder optical system, and shielding and transmission states of light incident on the element are controlled by turning on and off the applied voltage for performing various displays. Such cameras frequently use a light modulation element, which uses an TN or GH type liquid crystal element and which is brought into a non-transmission state by applying the voltage thereto (posi-type). However, since the voltage applied to transparent electrodes having a display pattern is controlled, the visual field of a finder is not entirely brought into the non-transmission state.
On the other hand, cameras using a light modulation element which uses a PDL (Polymer-Dispersed Liquid Crystal) or GH type liquid crystal element and which causes a transmission state by applying a voltage have also been proposed (nega-type). In this type of light modulation element, a non-transmission state is established when no voltage is applied.
A camera with a TTL type auto-focus (AF) system frequently has the problem of the presence of noise light entering from a finder. In normal use, this is little problem because a photographer looks through the finder. However, for example, when a photographer does not look through the finder, an undesirable light entering through an eyepiece enters the AF systems from the finder side, and sometime causes unexpected adverse effects on AF system.